Effects of phosphorolytic and cell wall-degrading enzymes on the performance of growing broilers fed wheat-based diets containing different calcium levels

Abstract

A study was conducted to determine the cumulative effects of phosphorolytic enzymes, cell wall-degrading enzymes, and citric acid and Ca levels on feed intake, BW gain (BWG), feed conversion, intestinal viscosity, and toe ash of broilers (d 1 to 21) fed wheat-based diets. Broilers were fed the following six diets at either 0.59, 0.69, or 0.79% Ca: 1) a negative control (NC) diet, 0.17% available P; 2) NC + 750 phytase units/kg diet; (3) phytase + 3,156 units of acid phosphatase/kg diet; 4) phytase + acid phosphatase + 1,900 units of pectinase/g diet; 5) phytase + acid phosphatase + pectinase + 3% citric acid; and (6) NC plus 0.24% available P. The 18 dietary treatments were fed to four pen replicates of eight birds each. Phytase addition at the low Ca level increased BWG, improved feed intake and conversion and toe ash, and reduced intestinal viscosity and ileal length. Subsequent addition of acid phosphatase, at 0.69% Ca, resulted in increases in BWG, 42%; feed intake 32%; feed conversion 7.5%; and toe ash, 63% over the NC diet. Pectinase addition produced further improvements in 21-d BWG and feed intake at 0.59 and 0.79% Ca, increased toe ash in chicks fed 0.79% Ca, and reduced intestinal viscosity. Supplementation of wheat-based 0.17% available P diets with phytase and acid phosphatase and with appropriate concentrations of pectinase, citric acid, and Ca significantly improved BWG, feed intake and conversion and intestinal viscosity over the 0.41% available P diets. Bone mineralization of chicks fed phytase + acid phosphatase and 0.69% Ca and those fed phytase + acid phosphatase + pectinase + citric acid and 0.59% Ca was similar to that of chicks fed the 0.41% available P diets.

The effect of adding exogenous phytase to nutrient-reduced corn- and wheat-based diets on performance and egg quality of two strains of laying hens

“…Scott et al (1998b) reported that the wheat cultivar that was used in this trial was improved considerably by the addition of xylanase, indicating that a high level of xylans may have been present. Recently similar interactions between enzymes were reported for broilers fed wheat (Zyla et al 2000).…”

Effects of supplemental phytase on performance and tibia ash of broilers fed different cereals based diets

“…These results were obtained for maize-soybeans based diets. Zyla et al (2000) showed that phytase addition to wheat-soya based diets had no significant effect on bone mineralization. This different observation can be explained by Underwood's finding (1981) that the Ca to nonphytate phosphorus ratio beyond 2 : 1 reduces bioavailability of Ca and P due to the formation of insoluble calcium-phosphate complex in the chicken gut.…”

“…Zyla et al (2000) showed that supplementation of 750 PU/kg to wheat based diet increased body weight gain, feed consumption and phosphorus retention. Supplementation of phytase (1 200 PU/kg) improved the digestibility of protein and amino acids in maize, sorghum and wheat based diets, but the magnitude of response varied between cereals (Ravindran et al, 1999).…”

Effects of supplemental phytase on nutrient excretion and retention in broilers fed different cereal based diets

“…The magnitude of response varied between cereals. Supplemental phytase improved phosphorus retention in broilers fed wheat (Leske and Coon, 1999;Zyla et al, 2000), wheat midds, barley, defatted rice bran and canola based diets (Leske and Coon, 1999).…”